cmd/compile/internal/syntax: fast Go syntax trees, initial commit.

Syntax tree nodes, scanner, parser, basic printers.

Builds syntax trees for entire Go std lib at a rate of ~1.8M lines/s
in warmed up state (MacMini, 2.3 GHz Intel Core i7, 8GB RAM):

$ go test -run StdLib -fast
parsed 1074617 lines (2832 files) in 579.66364ms (1853863 lines/s)
allocated 282.212Mb (486.854Mb/s)
PASS

Change-Id: Ie26d9a7bf4e5ff07457aedfcc9b89f0eba72ae3f
Reviewed-on: https://go-review.googlesource.com/27195
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/cmd/compile/internal/syntax/nodes.go

@@ -0,0 +1,425 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syntax
+
+// ----------------------------------------------------------------------------
+// Nodes
+
+type Node interface {
+	aNode()
+}
+
+type node struct {
+	doc  *Comment // nil means no comment(s) attached
+	pos  uint32
+	line uint32
+}
+
+func (*node) aNode() {}
+
+func (n *node) init(p *parser) {
+	n.pos = uint32(p.pos)
+	n.line = uint32(p.line)
+}
+
+// ----------------------------------------------------------------------------
+// Files
+
+type File struct {
+	PkgName  *Name
+	DeclList []Decl
+	Pragmas  []Pragma
+	Lines    int
+	node
+}
+
+type Pragma struct {
+	Line int
+	Text string
+}
+
+// ----------------------------------------------------------------------------
+// Declarations
+
+type (
+	Decl interface {
+		Node
+		aDecl()
+	}
+
+	ImportDecl struct {
+		LocalPkgName *Name // including "."; nil means no rename present
+		Path         *BasicLit
+		Group        *Group // nil means not part of a group
+		decl
+	}
+
+	ConstDecl struct {
+		NameList []*Name
+		Type     Expr   // nil means no type
+		Values   Expr   // nil means no values
+		Group    *Group // nil means not part of a group
+		decl
+	}
+
+	TypeDecl struct {
+		Name  *Name
+		Type  Expr
+		Group *Group // nil means not part of a group
+		decl
+	}
+
+	VarDecl struct {
+		NameList []*Name
+		Type     Expr   // nil means no type
+		Values   Expr   // nil means no values
+		Group    *Group // nil means not part of a group
+		decl
+	}
+
+	FuncDecl struct {
+		Attr map[string]bool // go:attr map
+		Recv *Field          // nil means regular function
+		Name *Name
+		Type *FuncType
+		Body []Stmt // nil means no body (forward declaration)
+		decl
+	}
+)
+
+type decl struct{ node }
+
+func (*decl) aDecl() {}
+
+// All declarations belonging to the same group point to the same Group node.
+type Group struct {
+	dummy int // not empty so we are guaranteed different Group instances
+}
+
+// ----------------------------------------------------------------------------
+// Expressions
+
+type (
+	Expr interface {
+		Node
+		aExpr()
+	}
+
+	// Value
+	Name struct {
+		Value string
+		expr
+	}
+
+	// Value
+	BasicLit struct {
+		Value string
+		Kind  LitKind
+		expr
+	}
+
+	// Type { ElemList[0], ElemList[1], ... }
+	CompositeLit struct {
+		Type     Expr // nil means no literal type
+		ElemList []Expr
+		NKeys    int // number of elements with keys
+		expr
+	}
+
+	// Key: Value
+	KeyValueExpr struct {
+		Key, Value Expr
+		expr
+	}
+
+	// func Type { Body }
+	FuncLit struct {
+		Type *FuncType
+		Body []Stmt
+		expr
+	}
+
+	// (X)
+	ParenExpr struct {
+		X Expr
+		expr
+	}
+
+	// X.Sel
+	SelectorExpr struct {
+		X   Expr
+		Sel *Name
+		expr
+	}
+
+	// X[Index]
+	IndexExpr struct {
+		X     Expr
+		Index Expr
+		expr
+	}
+
+	// X[Index[0] : Index[1] : Index[2]]
+	SliceExpr struct {
+		X     Expr
+		Index [3]Expr
+		expr
+	}
+
+	// X.(Type)
+	AssertExpr struct {
+		X Expr
+		// TODO(gri) consider using Name{"..."} instead of nil (permits attaching of comments)
+		Type Expr
+		expr
+	}
+
+	Operation struct {
+		Op   Operator
+		X, Y Expr // Y == nil means unary expression
+		expr
+	}
+
+	// Fun(ArgList[0], ArgList[1], ...)
+	CallExpr struct {
+		Fun     Expr
+		ArgList []Expr
+		HasDots bool // last argument is followed by ...
+		expr
+	}
+
+	// ElemList[0], ElemList[1], ...
+	ListExpr struct {
+		ElemList []Expr
+		expr
+	}
+
+	// [Len]Elem
+	ArrayType struct {
+		// TODO(gri) consider using Name{"..."} instead of nil (permits attaching of comments)
+		Len  Expr // nil means Len is ...
+		Elem Expr
+		expr
+	}
+
+	// []Elem
+	SliceType struct {
+		Elem Expr
+		expr
+	}
+
+	// ...Elem
+	DotsType struct {
+		Elem Expr
+		expr
+	}
+
+	// struct { FieldList[0] TagList[0]; FieldList[1] TagList[1]; ... }
+	StructType struct {
+		FieldList []*Field
+		TagList   []*BasicLit // i >= len(TagList) || TagList[i] == nil means no tag for field i
+		expr
+	}
+
+	// Name Type
+	//      Type
+	Field struct {
+		Name *Name // nil means anonymous field/parameter (structs/parameters), or embedded interface (interfaces)
+		Type Expr  // field names declared in a list share the same Type (identical pointers)
+		node
+	}
+
+	// interface { MethodList[0]; MethodList[1]; ... }
+	InterfaceType struct {
+		MethodList []*Field
+		expr
+	}
+
+	FuncType struct {
+		ParamList  []*Field
+		ResultList []*Field
+		expr
+	}
+
+	// map[Key]Value
+	MapType struct {
+		Key   Expr
+		Value Expr
+		expr
+	}
+
+	//   chan Elem
+	// <-chan Elem
+	// chan<- Elem
+	ChanType struct {
+		Dir  ChanDir // 0 means no direction
+		Elem Expr
+		expr
+	}
+)
+
+type expr struct{ node }
+
+func (*expr) aExpr() {}
+
+type ChanDir uint
+
+const (
+	_ ChanDir = iota
+	SendOnly
+	RecvOnly
+)
+
+// ----------------------------------------------------------------------------
+// Statements
+
+type (
+	Stmt interface {
+		Node
+		aStmt()
+	}
+
+	SimpleStmt interface {
+		Stmt
+		aSimpleStmt()
+	}
+
+	EmptyStmt struct {
+		simpleStmt
+	}
+
+	LabeledStmt struct {
+		Label *Name
+		Stmt  Stmt
+		stmt
+	}
+
+	BlockStmt struct {
+		Body []Stmt
+		stmt
+	}
+
+	ExprStmt struct {
+		X Expr
+		simpleStmt
+	}
+
+	SendStmt struct {
+		Chan, Value Expr // Chan <- Value
+		simpleStmt
+	}
+
+	DeclStmt struct {
+		DeclList []Decl
+		stmt
+	}
+
+	AssignStmt struct {
+		Op       Operator // 0 means no operation
+		Lhs, Rhs Expr     // Rhs == ImplicitOne means Lhs++ (Op == Add) or Lhs-- (Op == Sub)
+		simpleStmt
+	}
+
+	BranchStmt struct {
+		Tok   token // Break, Continue, Fallthrough, or Goto
+		Label *Name
+		stmt
+	}
+
+	CallStmt struct {
+		Tok  token // Go or Defer
+		Call *CallExpr
+		stmt
+	}
+
+	ReturnStmt struct {
+		Results Expr // nil means no explicit return values
+		stmt
+	}
+
+	IfStmt struct {
+		Init SimpleStmt
+		Cond Expr
+		Then []Stmt
+		Else Stmt // either *IfStmt or *BlockStmt
+		stmt
+	}
+
+	ForStmt struct {
+		Init SimpleStmt // incl. *RangeClause
+		Cond Expr
+		Post SimpleStmt
+		Body []Stmt
+		stmt
+	}
+
+	SwitchStmt struct {
+		Init SimpleStmt
+		Tag  Expr
+		Body []*CaseClause
+		stmt
+	}
+
+	SelectStmt struct {
+		Body []*CommClause
+		stmt
+	}
+)
+
+type (
+	RangeClause struct {
+		Lhs Expr // nil means no Lhs = or Lhs :=
+		Def bool // means :=
+		X   Expr // range X
+		simpleStmt
+	}
+
+	TypeSwitchGuard struct {
+		// TODO(gri) consider using Name{"..."} instead of nil (permits attaching of comments)
+		Lhs *Name // nil means no Lhs :=
+		X   Expr  // X.(type)
+		expr
+	}
+
+	CaseClause struct {
+		Cases Expr // nil means default clause
+		Body  []Stmt
+		node
+	}
+
+	CommClause struct {
+		Comm SimpleStmt // send or receive stmt; nil means default clause
+		Body []Stmt
+		node
+	}
+)
+
+type stmt struct{ node }
+
+func (stmt) aStmt() {}
+
+type simpleStmt struct {
+	stmt
+}
+
+func (simpleStmt) aSimpleStmt() {}
+
+// ----------------------------------------------------------------------------
+// Comments
+
+type CommentKind uint
+
+const (
+	Above CommentKind = iota
+	Below
+	Left
+	Right
+)
+
+type Comment struct {
+	Kind CommentKind
+	Text string
+	Next *Comment
+}